1. Field of the Invention
The present invention generally relates for filtering means and more particularly pertains to an improved liquid filtering system for agricultural and industrial water and the like.
2. Prior Art
Various types of water filtration systems are in use to upgrade water for agricultural, industrial and domestic purposes. One commercial type of filtering system comprises a large metal or plastic tank having an inlet and an outlet remotely located from each other and containing in the central cavity of the tank adjacent the outlet a very large body of crushed rock or the like aggregate material cemented together by epoxy resin into a self-supporting porous mass. In some instances, the upstream portion of this mass is formed with fine particle size aggregate while the downstream portion is formed with larger size aggregate. Usually, the mass is formed in situ, with a bottom grating or screen supporting the mass slightly above the tank outlet. The mass is designed to occupy the entire bottom of the tank to prevent water from bypassing it before exiting the tank. The mass is extremely heavy and normally cannot be removed from the tank for replacement or repair unless the tank is torn apart. While this type of water filtration system is efficient, because of its extremely high weight it is costly to ship to the locations where it must be installed to be used. As noted above, it normally does not have the capability of being repaired without extensive cost.
In utilizing conventional filter tanks, it is necessary to periodically back wash to remove deposited solids from the filtering medium. Thus, water or other wash liquid is passed up the outlet into and through the tank and exits the inlet or back wash by-pass. Channeling of the wash liquid up through the filtering medium frequently occurs because the wash liquid does not contact the filtering medium across a broad front. This results in improper and inadequate washing of the filtering medium, reducing its life and utility.
Accordingly, there is a need for an improved type of water filtration system which can also be used in the filtration of other liquids. Such a system should be inexpensive, relatively light in weight and be capable of having the filter repaired and replaced as needed without necessitating destruction of the tank in which the filter is secured. The system should also be capable of being provided in a form which effectively prevents blowup of the tank during back washing if the pores of the filter become plugged. In conventional large mass filters, as described above, the filters or tank may blow up if the filters are plugged and the tank is back washed, causing destruction of the filtration system. Moreover, the system should feature easy, efficient and complete back washing to restore the integrity of the filtering medium.